-85.71% is the change from 210 to 30
Calculation steps:
[( 30 - 210 ) ÷ 210] x 100 = -85.71%
Formula
Percentage change = [(30 - 210) / 210] x 100
Subtract the new number by the original number
30 - 210 = -180
-180 ÷ 210 = -0.8571428571428571
-0.8571428571428571 x 100 = -85.71%